TechCrunch reports that development of Mac OS X 10.7 Lion is moving along smoothly and is actually ahead of schedule. The current developer preview of 10.7 Lion is pretty stable but is not without its bugs, lockups, and crashes. Apple has been at work improving the operating system and is reportedly actually almost ready to release a golden master build of the next-generation Mac operating system.

Apple is gearing up to deploy an OS X Lion update to developers that they may be classifying as the “GM1″ release, we’re hearing. “GM” or “Golden Master” is a title reserved for software that is complete. But from what we’ve heard, this is only the initial Golden Master candidate.

A golden master (GM) software release is the stage in which the software’s development is complete and ready to print. Probably in Lion’s case, though, a GM means ready to upload to the Mac App Store. Although GMs usually mean the software will be shipping out to consumer’s soon, TechCrunch says there will be multiple GMs – like iOS 4.2 – with the one coming soon being labeled as GM1.

Back at Lion’s announcement in October 2010, Apple said the OS would ship sometime during summer 2011. At this point, development is in its far stages s0 it’s a safe bet that we’ll be hearing more about it at Apple’s early-June World Wide Developers Conference (WWDC). Mac OS X Lion brings many new features to the Mac including Mission Control (Spaces, Expose combined), Launchpad (iOS-like home screens), new Multi-Touch gestures, full-screen applications, an iPad-like mail application, AirDrop WiFi file sharing, and built-in server functionality.